An alarm system includes an alarm panel to provide alarm messages to an alarm monitoring station via an analog landline telephone network, such as an analog Public Switched Telephone Network (PSTN) and/or an analog plain old telephone service (POTS) network. The alarm panel may provide the alarm message, via the analog landline telephone network, by placing a telephone call and sending a dual-tone multi-frequency (DTMF) signal (e.g., a series of audible tones approximately 50 milliseconds (ms) to approximately 100 ms in length). The alarm panel may need to disconnect devices in a telephone network, associated with the facility (e.g., a facility telephone network), to ensure that the facility telephone network is available for use by the alarm system to place the telephone call. The alarm system may include an alarm signal processing device that interferes with a disconnection switch that is used to disconnect the devices in the facility telephone network.